Evaluation of anti-oxidative, antimicrobial and anti-diabetic potential of Adiantum venustum and identification of its phytochemicals through GC-MS.

The present study aimed to explore antioxidant, antimicrobial and anti-diabetic properties of the fern Adiantum venustum. The TPC (total phenolic content) of methanolic extract of the plant was 247.95±0.0007μg of Gallic acid equivalents per gram of dried extract (mg GAE/g). The highest TPC was in n-butanolic fraction, which was 981.45±0.1562mg GAE/g. Hexane fraction showed lowest TPC (256.95±0.0420mg GAE/g). Ethyl acetate fraction exhibited highest total flavonoid content (TFC), i.e., 62.0±0.050mg of Rutin equivalents per gram of sample. DPPH (1,1-diphenyl-2- picryl hydrazyl) radical scavenging activity of the plant was significant. n-Butanolic fraction was most potent with IC50 being 1.06mg/mL. The IC50 of methanolic extract was 1.50mg/mL, that of aqueous fraction was 2.51 mg/mL, and that of chloroform fraction was 2.65mg/mL. Antibacterial potential of the fern was tested against two Gram-positive bacterial strains, Pseudomonas aeruginosa and Escherichia coli and two Gram-negative bacterial strains, Bacillus subtilis and Staphylococcus aureus. n-Butanolic fraction showed highest zone of inhibition (ZOI, 25.13±1.237 mm) against P. aeruginosa. Ethyl acetate fraction was most active (ZOI, 15.75±1.060 mm) against S. aureus. Against E. coli, aqueous and n-butanolic fractions were most active (ZOI, 14.75±0.353 and 14.50±0.707mm, respectively). Minimum inhibitory concentration (MIC) of methanolic extract against B. subtilis was as low as 1.98mg/mL. The hexane fraction was least toxic against all the fractions. The plant displayed significant alpha-amylase inhibitory activity. Chloroform fraction was most effective with lowest IC50 (1.10mg/mL) followed by ethyl acetate fraction (1.92mg/mL). A. venustum is rich in phenolics and has substantial antioxidant, antimicrobial and alpha-amylase inhibitory potential.